Posner was a Manticoran citizen and a petty officer of the Royal Manticoran Navy. Holding the rank of Senior Chief Petty Officer, he served as the senior non-commissioned officer in the tactical department of the heavy cruiser HMS Gauntlet, and was very much in charge of the ship's midshipmen. He fought in the Battle of Tiberian in June 1918 PD. (HHA4.6: TSotS)